The SENTINEL line of filter bags by Eaton was designed for bypass-free construction. It features all welded bag seams and a pressure sealing ring that make for an effective and efficient filter bag. Description NMO-25-P01E-E-50 denotes a 25 micron size 01 filter bag. Eaton's SENTINEL bags are constructed using welded seams as opposed to sewn. This makes for a stronger seam and eliminates needle holes which can allow bypass. This bag is made of Nylon monofilament with a plastic Polypropylene ring. Comes in box quantities of 50.